The two leading bourses NSE and BSE have written to some of the listed Tata Group companies in this matter.

Mistry, on Wednesday, wrote an email to board members of the Tata Group and termed the decision as “shocking”. Mistry claimed he was never given a free hand and Tata’s Nano project was taken up as it was Ratan Tata’s dream.

In his e-mail, Mistry said the group took emotional decisions rather than being practical.

A notice on the BSE said, "The exchanges have sought clarification from the company with respect to a news article appearing on Bloomberg on October 26, 2016 titled 'Ousted Tata Chief Says Group Faces $18 Billion in Writedowns'. The reply is awaited." The BSE, NSE have written to Tata Motors, Tata Steel, Tata Power and other group companies.

Tata Power, in its reply, stated the article was, "with comments purported to have been made by ex-chairman of Tata Sons regarding the company's Mundra ultra power project. The company has always made all relevant disclosures, as required, and has no further comments to offer."

Replies from other Tata Group companies are awaited.

Meanwhile, markets regulator SEBI (Securities Exchange Board of India) has been following the developments at the Tata Group closely. "After the exchanges report to us on these developments (at the Tata Group), we will decide our next course of action," a top regulatory official told ET.